Bone grafting material in combination with Osteogain for bone repair: a rat histomorphometric study

Enamel matrix derivative (EMD) has been successfully used for the regeneration of periodontal tissues including new cementum, periodontal ligament, and alveolar bone. Combination of EMD with bone grafting materials has however generated variable clinical results. Recently, we have demonstrated that a new formulation of EMD in a liquid carrier system (OsteogainA (R)) has improved physicochemical properties for the adsorption of EMD to a bone grafting material. The aim of the present study was to investigate the regenerative potential of OsteogainA (R), in combination with a bone graft, on new bone formation in a rat femur defect model. Fifty-four critically sized femur defects (3 mm in diameter) were created bilaterally in 27 rats and treated following the group allocation: (1) drilled unfilled control, (2) a natural bone mineral (NBM), and (3) NBM + OsteogainA (R). All defects were histologically analyzed at 2, 4, and 8 weeks after surgical intervention. Micro-CT analysis, hematoxylin and eosin (H&E) staining, and Safranin O staining were performed to quantify new bone formation. Significantly more new bone formation was observed in defects treated with NBM + OsteogainA (R) at both 4 and 8 weeks when compared to NBM alone and the control unfilled defects (P < 0.05). Histologically, the formation of more mature mineralized bone with the presence of osteocytes were found more commonly in defects treated with OsteogainA (R) + NBM at 8 weeks post-healing when compared to NBM alone. The present study demonstrate that OsteogainA (R) in combination with a bone grafting material improves the speed and quality of new bone formation in rat osseous defects. Future clinical research are now warranted to fully characterize the benefits of OsteogainA (R), a new formulation of enamel matrix proteins delivered in liquid formation when used in combination with a bone grafting material.